(1) Field of the Invention
This invention relates to lubricant compositions containing a major amount of an oil of lubricating viscosity and a minor amount of at least one amino phenol which are useful in two-cycle internal combustion engines. More particularly, it relates to such oils containing amino phenols having at least one hydrocarbon-based group of at least about 10 aliphatic carbon atoms. Since two-cycle engine oils are often combined with fuels before or during use, this invention also relates to two-cycle fuel-lubricant mixtures.
(2) Prior Art
U.S. Pat. No. 2,197,835 describes the formation of metal salts of aromatic amines, said amines being formed by nitration followed by reduction of wax-substituted hydroxy-aromatic hydrocarbons. These metal salts can be incorporated in mineral oils to depress their pour point and increase their viscosity indices.
U.S. Pat. Nos. 2,502,708 and 2,571,092 both disclose the nitration and subsequent hydrogenation to an amine of cardanol. This amino cardanol is said to be useful as an anti-oxidant for mineral oils, fats and petroleum oils. Cardanol, also known as anacardol, is also said to be a mixture of 3-pentadecylphenol, 3-(8'-pentadecenyl)phenol, 3-(8':11'-pentadecadienyl)phenol and 3-(8:11:14'-pentadecatrienyl)phenol. Formulae presented in both the '092 and '708 patents as well as the chemical literature (see the Dictionary of Organic Compounds, Vol. 1, Oxford University Press, N.Y., 1965, page 229) show that the C.sub.15 substituent in cardanol is meta position to the hydroxy group.
U.S. Pat. No. 2,859,251 discloses the alkylation of ortho-, para-, and meta-amino phenols with olefin polymers having from 6 to 18 carbon atoms per molecule in the presence of a catalytic complex formed by mixing hydrogen fluoride with boron trifluoride and an iron group metal flouride. The '251 patent fails to disclose whether the alkyl groups in the product mixture are bonded to a carbon, nitrogen and/or oxygen atom.
(3) General Background
Over the past several decades the use of spark-ignited two-cycle (two-stroke) internal combustion engines including rotary engines such as those of the Wankel type has steadily increased. They are presently found in power lawn mowers and other power-operated garden equipment, power chain saws, pumps, electrical generators, marine outboard engines, snow mobiles and the like.
The increasing use of two-cycle engines coupled with increasing severity of the conditions in which they have operated has led to an increasing demand for oils to adequately lubricate such engines. Among the problems associated with lubrication of two-cycle engines are piston ring sticking, rusting, lubrication failure of connecting rod and main bearings and the general formation on the engine's interior surfaces of carbon and varnish deposits. The formation of varnish is a particularly vexatious problem since the build-up of varnish on piston and cylinder walls is believed to ultimately result in ring sticking which leads to failure of the sealing function of piston rings. Such seal failure causes loss of cylinder compression which is particularly damaging in two-cycle engines because they depend on suction to draw the new fuel charge into the exhausted cylinder. Thus, ring sticking can lead to deterioration in engine performance and unnecessary consumption f fuel and/or lubricant. These additives can also reduce spark plug fouling and engine port plugging problems.
The unique problems and techniques associated with the lubrication of two-cycle engines has led to the recognition by those skilled in the art of two-cycle engine lubricants as a distinct lubricant type. See, for example, U.S. Pat. Nos. 3,085,975, 3,004,837 and 3,753,905.
The invention described herein is directed to alleviation of these problems through the provision of effective additives for two-cycle engine oils and oil-fuel combinations which eliminate or reduce engine varnish deposits and piston ring seal failure.
(4) Objects
Therefore, it is an object of this invention to provide novel lubricants and fuel-lubricant mixtures for two-cycle engines.
It is a further object of this invention to provide novel means for lubricating two-cycle engines.
Other objects will be apparent to those skilled in the art upon review of the present specification.